The phosphorous cycle
- Phosphorous is an essential nutrient found in the macromolecules of humans and other organisms, including .
- The phosphorous cycle is slow. Most phosphorous in nature exists in the form of phosphate ion—.
- Phosphorous is often the limiting nutrient, or nutrient that is most scarce and thus limits growth, in aquatic ecosystems.
- When nitrogen and phosphorous from fertilizer are carried in runoff to lakes and oceans, they can cause eutrophication, the overgrowth of algae. The algae may deplete oxygen from the water and create a dead zone.